1. SOYA BEAN OIL BASED
LUBRICANTS FOR DIESEL ENGINES
A PROJECT REPORT
Submitted By
T.NAVANEETHA KRISHNAN 070111303030
K.NARESHKUMAR 070111303029
in partial fulfillment for the award of the degree
of
BACHELOR OF ENGINEERING
IN
MECHANICAL ENGINEERING
INSTITUTE OF ROAD AND TRANSPORT TECHNOLOGY
ERODE-638 316
ANNA UNIVERSITY COIMBATORE 641047
MAY 2010
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2. ii

3. CONTENTS
CHAPTER No. TITLE PAGE No.
List of Tables v
List of Figures vi
List of Abbreviations vii
Abstract viii
1. Introduction 1
1.1 Need for alternate lubricants 1
1.2 Lubricating oil 2
2. Properties of Lubricating Oil 3
2.1 Flash Point 3
2.2 Fire Point 3
2.3 Cloud Point 3
2.4 Pour Point 3
2.5 Specific Gravity 3
2.6 Sulphur Content 3
2.7 Adhesiveness 4
2.8 Kinematic Viscosity 4
2.9 Viscosity Index (VI) 4
2.10 Volatility 5
3. Scope of This Project 6
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4. 4. Vegetable Oils and Esterification 7
4.1 Introduction 7
4.2 Production of soys bean methyl ester 7
4.2.1 Transesterification process 8
4.2.2 Materials required 9
4.2.3 Method adopted 9
4.2.4 Soap formation 10
4.2.5 Separation & draining of glycerol 11
4.3 Washing procedure 12
4.3.1 Significance of washing 12
4.3.2 Removal of Unreacted methanol 12
4.3.3 Washing techniques 13
4.3.4 Washing technique adopted 15
4.3.5 Drying of washed methyl ester 16
5. Determination of Viscosity 17
6. Determination of Viscosity Index 19
7. Results of the Lubricant Properties 20
8. Conclusion 21
9. References 22
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5. LIST OF TABLES
TABLE No. TITLE PAGE No.
2.1 Desired Properties of Lubricants 5
5.1 Kinematic Viscosity of some oil samples 18
6.1 Calculation of Viscosity Index 19
7 .1 Results of the lubricant properties 20
LIST OF FIGURES
FIG No. TITLE PAGE No.
4.1 Transesterification reaction 8
4.2 Preparation of sodium methoxide solution 10
& adding it to oil
4.3 Separation & Draining of Glycerol 11
4.4 Removal of Unreacted methanol 13
4.5 Washing Techniques 14
4.6 Washing Technique Adopted 15
5.1 Determination of viscosity using 17
Red Wood Viscometer.
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6. LIST OF ABBREVIATIONS
1. ASTM-American Society for Testing and Material Standard
2. cSt-Centistroke
3. FFA-Free Fatty Acid
4. SBME-Soya Bean Methyl Ester
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7. ABSTRACT
Recently much effort has been focused on research and development of new types of
lubricating oils to reduce wear, friction and corrosion in engine applications. Vegetable oils are
based on soya bean, sunflower, castor, rapeseed, corn, canola and soya bean. The vegetable
lubricants are environmentally friendly alternative to mineral oils since they are biodegradable.
The vegetable oils are having many advantages like high viscosity index, low friction coefficient,
high flash point, low volatile etc., over mineral oils. Soya bean oil Methyl ester based biodiesel is
a viable alternative to fossil fuels. Apart from its use as an alternative fuel, Soya bean oil methyl
esters have the potential to be used as lubricants due to its inherently favorable lubricity and
viscosity index properties.
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8. 1. INTRODUCTION
“The important thing in science is not so much to obtain new facts
as to discover new facts of thinking about them.”
- SIR WILLIAM BIAGG
1.1 NEED FOR ALTERNATE LUBRICANTS
Historically, many mass and agricultural derived materials have been suggested as
alternative energy sources and the use of biodiesel as fuel presents a promising potential. These
sources are limited, and will be exhausted in the near future. .
It has necessitated the governments, research communities, and private organizations
around the world to look for alternative and renewable sources of energy due to the depletion of
petroleum reserves, increase in energy demands, unpredictability of fossil oil production, and
increased concerns of rising greenhouse gas emissions. To date, many alternatives have been
researched and demonstrated but only a few have been proven to be practically feasible in terms
of availability, economics, public and environmental safety, and simplicity of use. One such
possible alternative is biodiesel from vegetable oils, used at 100% or blended with diesel fuel for
compression-ignition type engines.
Soya bean oil is relatively cheap when compared to mineral oils and other vegetable oils.
In addition, soya bean oil is safer and environmentally friendly. Crankcase lubricants are either
petroleum based or mineral oil based. Prices of these synthetic oils are significantly higher
compared to vegetable oil-based lubricants. Although soya bean oil and its derivatives like
methyl esters have many properties that are conducive as crankcase oils, in depth engine studies
on the functionality of these oil forms are limited.
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9. Use of bio based lubricants is expected to increase in next five to ten years due to
growing regulatory concerns on existing lubricants. Most of the synthetic lubricants in present
market are made of esters and offer better thermal and oxidative stability. As esters can be
manufactured from vegetable oils by transesterification, lubricants can be potentially
manufactured from vegetable oils.
1.2 LUBRICATING OIL
The main purpose of lubricants is to lubricate moving parts of the vehicle to reduce
friction and wear and tear by providing smoothing, trouble free performance for increased length
of time. Because heat and wear are associated with friction, both effects can be minimized by
reducing the coefficient of friction between the contacting surfaces. Lubrication is also used to
reduce oxidation and prevent rust; to provide insulation in transformer applications; to transmit
mechanical power in hydraulic fluid power applications; and to seal against dust, dirt, and water.
The primary objectives of the lubricants in automobiles are to reduce wear and friction
between moving parts, to act as cooling medium for removing heat, to keep the engine parts
clean especially piston rings and ring grooves, oil ways and filters. It also forms a good seal
between the piston rings and cylinder walls and absorbs and carries away harmful substances
from incomplete combustion. To prevent metallic components from corrosive attack by the acid
formed during the combustion process. It should also resist oxidation which causes sludge and
lacquers.
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10. 2. PROPERTIES OF LUBRICATING OIL
There are various properties that determine the quality of lubricating oil; the most
important one is the viscosity (measure of resistance to the flow of oil) of the oil and the various
other parameters that govern the quality of the oil are
2.1 Flash Point
The lowest temperature at which the lubricating oil will flash when a small flame is
introduced across its surface.
2.2 Fire Point
When the oil is heated beyond the flash point, the minimum temperature at which the oil
will burn continuously.
2.3 Cloud Point
The oil changes from liquid state to solid state or a plastic state when subjected to lower
temperatures, in some cases the oil starts solidifying which may appear cloudy known as the
cloud point
2.4 Pour Point
The lowest temperature at which the lubricating oil will pour. The pour point of oil is the
indication of its ability to move at lower temperatures.
2.5 Specific Gravity
The specific gravity is the measure of density of the oil which is measured using a
hydrometer that is made to float in the oil.
2.6 Sulphur Content
If the sulphur content is present in considerable amount in the lubricating oil then it
promotes corrosion. The corrosion shows the amount of sulphur content.
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11. 2.7 Adhesiveness
It is the property of the lubricating oil due to which the of particles stick to the metal
surfaces.
2.8 Kinematic Viscosity
Kinematic viscosity may be defined as the quotient of the absolute viscosity in
centipoises divided by the specific gravity of a fluid, both at the same temperature. The unit of
kinematic viscosity is stoke or centistokes (1/100th of a stoke).
Viscosity of engine oil is one of its most important and most evident properties. For
engine oil, a small change in viscosity with temperature (high viscosity index) is desirable to
provide a wide range of operating temperatures over which given oil will provide satisfactory
lubrication.
A high viscosity implies high resistances to flow while a low viscosity indicates a low
resistance to flow. Viscosity varies inversely with temperature. Viscosity is also affected by
pressure; higher pressure causes the viscosity to increase, and subsequently the load-carrying
capacity of the oil also increases. This property enables use of thin oils to lubricate heavy
machinery.
2.9 Viscosity Index (VI)
Viscosity Index is an arbitrary number used to characterize the variation of the kinematic
viscosity of a fluid with change in temperature. Viscosity index can be classified as follows: low
VI - below 35; medium VI - 35 to 80; high VI - 80 to 110; very high VI - above 110. The higher
the viscosity index, the smaller the relative change in viscosity with temperature.
Therefore, a fluid that has a high viscosity index can be expected to undergo very little
change in viscosity with temperature extremes and is considered to have a stable viscosity. A
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12. fluid with a low viscosity index can be expected to undergo a significant change in viscosity as
the temperature fluctuates. Oil with a VI of 95 to 100 would change less than one with a VI of
80.
2.10 Volatility
It is the ability of any fluid to change from its physical state of liquid to vapor at elevated
temperatures. Volatility characteristics are essentially inherent in the choice of base stock oil for
a particular type of service. Viscosity gives an indication of the volatility of a lubricant in
general, the lower its viscosity the higher its volatility.
Table 2.1 Desired Properties of Lubricants
Properties Requirements
Kinematic viscosity at 40 deg. C Low
Kinematic viscosity at 100 deg. C Low
Viscosity index High
Total acid number Low
(mg-KOH/gm)
Saponification valve High
(mg-KOH/gm)
Pour point (deg. C) Low
Flash point (deg. C) High
Iodine value Low
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13. 3. SCOPE OF THIS PROJECT
Soya Bean Methyl Ester (SBME) is a viable alternative to fossil fuels. Apart from its use
as an alternative fuel, soya bean oil methyl esters have the potential to be used as lubricants due
to its inherently favorable lubricity and viscosity index properties
While using the esters of vegetable oil, still some limitations prevail such as low
oxidation stability, low thermal stability, low temperature, etc. On the other hand, the oxidation
of vegetable oil is a main problem encountered when it is used as a lubricant in engines.
Generally the thermal stability will improve to some extent when the ester of vegetable oil from
trans-esterification process and it is clearly studied later.
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14. 4. VEGETABLE OILS AND ESTERIFICATION
4.1 INTRODUCTION
Vegetable oils are a viable and renewable source of environmentally favorable oils.
Recently, much effort has been focused on research and development of new types of lubricating
oil additives to reduce wear and friction in the tribological systems. It has been noted that the use
of additives to improve the lubricating capacity and durability of oil plays an important role in
the wear and friction process of materials.
4.2 PRODUCTION OF SOYA BEAN METHYL ESTER
Generally, there are three basic ways for the production of methyl esters from oils and
fats:
 Base catalyzed transesterification of the oil (triglycerides) with methanol;
 Direct acid catalyzed esterification of the free fatty acids (FFA) with methanol;
 Conversion of the oil to FFA followed their esterification as described above.
The majority of the methyl esters are produced using the base catalyzed reaction because it is the
 Most economic for several reasons
 Low temperature and pressure
 High yields and short reaction times
 Direct conversion process
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15. 4.2.1 TRANSESTERIFICATION PROCESS
Transesterification is the process of using an alcohol (e.g., methanol or ethanol) in the
presence of a catalyst, such as sodium hydroxide or potassium hydroxide, to chemically break
the molecule of the raw renewable oil into methyl or ethyl esters of the renewable oil with
glycerol as a by-product which is described in Figure 3.4. A catalyst is always added to the
transesterification system to improve the reaction rate.
Transesterification consists of a number of consecutive, reversible reactions. Diglycerides
and monoglycerides are the intermediates in this process. The triglyceride is converted stepwise
to Diglycerides, monoglycerides and finally glycerol. The reactions are reversible, although the
equilibrium lies towards the production of fatty acid esters and glycerol. A little excess of
alcohol is used to shift the equilibrium towards the formation of esters. In presence of excess
alcohol, the foreword reaction is pseudo-first order and the reverse reaction is found to be second
order. It was also observed that transesterification is faster when catalyzed by alkali.
Transesterified renewable oils have proven to be a viable alternative diesel engine fuel with
characteristics similar to those of diesel fuel. The need for going to Ester is due to its better
Viscosity Index, Thermal Stability and Oxidation Stability than that of Crude Oil.
Fig 4.1 Transesterification reaction
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16. 4.2.2 MATERIALS REQUIRED
The materials required for the preparation of Soya bean Methyl Ester are listed below.
 Soya bean oil
 Separating funnel
 Heater and Thermometer
 Alcohol (methanol/ethanol)
 Beaker and Measuring flask
 Catalyst (NaOH/KOH)
 Agitator
 Air pump
4.2.3 METHOD ADOPTED
Have all the materials warm, room temperature at the coolest, 130°F at the warmest. Put
on the respirator, goggles, and gloves. Place 1fluid cup of methanol in the blender. Measure out
3.5 grams of sodium hydroxide from a new container and place it in the methanol in the blender.
Put the top on the blender and blend on low speed for about five minutes. Shut off the blender.
The mixture in the blender is now sodium methoxide, a strong base. Avoid getting this on
anything, especially yourself.
Measure one quart of new Crude Soya bean oil and pour it into the sodium methoxide in
the blender. Put the lid on and blend at low speed for half an hour. Let the mixture settle at
room temperature for at least eight hours. The mixture is now composed of light-colored methyl
esters floating on top of heavier, darker glycerol. Using the hand pump, pump the light biodiesel
off the glycerol.
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17. Fig 4.2 Preparation of sodium methoxide solution & adding it to oil
4.2.4 SOAP FORMATION
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18. 4.2.5 SEPARATION & DRAINING OF GLYCEROL
Fig 4.3 Separation & Draining of Glycerol
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19. 4.3 WASHING PROCEDURE
4.3.1 Significance of washing
The Methyl ester produced with the process described above will work in some heating
and lighting equipment and may be used as a lubricant for diesel engines. Most impurities settle
out into the glycerol layer including unfiltered particulates, methanol, and glycerin. Some
sources encourage using unwashed Methyl ester, because washing Methyl ester is a time-
consuming process.
However, some alcohol, sodium hydroxide, and soap remain suspended throughout the
biodiesel after the transesterification is complete. Water in Methyl ester can lead to biological
growth as the fuel degrades. Unreacted methanol in the Methyl ester can result in explosion and
can corrode engine components. The catalyst, sodium hydroxide, can also attack other engine
components. Since the methanol and sodium hydroxide are chemical bases, unwashed biodiesel
is caustic and may damage diesel engine components. Soap is not a fuel and will reduce fuel
lubricity and cause injector coking and other deposits.
4.3.2 Removal of Unreacted methanol
Unreacted alcohol may be distilled from the Methyl ester and reclaimed for use in future
batches. Although alcohol reclamation is beyond the scope of this publication, note that
methanol boils at 148°F at sea level. Methanol can be driven from biodiesel by heating it; do
this outside or vent the methanol to the outside. Never breathe methanol fumes. A much better
and safer solution is to use a vacuum pump to lower the pressure of a closed tank. The methanol
can be collected and re-used. See the Resources section on methanol reclamation.
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20. Fig 4.4 Removal of unreacted methanol
4.3.3 Washing Techniques
There are three techniques for washing the Ester Agitation washing, Mist washing, and
Bubble washing.
The process of washing Methyl Ester involves mixing it with water. Water is heavier than
Methyl Ester and absorbs the excess alcohol, sodium hydroxide, and soap suspended in it. After
washing and settling, the water and the impurities in the water can be drained from the bottom of
the container. Several wash cycles are generally needed. The first water drained off the bottom
of the Methyl Ester will be milky, and the final wash water drained off will be clear. Excess
sodium hydroxide in the Methyl Ester will form soap when mixed with water, and it takes a
while for the soap to settle out. Depending on the method you use, it takes roughly as much
water as Methyl Ester for a wash cycle.
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21. Fig 4.5 Washing Techniques
Initial washings must involve gentle mixing to minimize the formation of soap that will
take time to settle out. However, you want the mixing to be thorough and for the water to be
dispersed throughout the Methyl Ester.
Agitation washing amounts to stirring water into the Methyl Ester, letting it settle, and draining it
off. Mist washing is spraying a fine mist of water over the surface of the Methyl Ester. Tiny
droplets of water fall through the Methyl Ester and pick up impurities on the way down.
Bubble washing is done by putting a bubbler in a layer of water beneath the Methyl Ester
in a container. As the bubbles rise they are coated with water, which picks up impurities as it
travels up and then back down through the Methyl Ester.
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22. 4.3.4 Washing Technique adopted
The washing technique here adopted is Agitation washing. Pour 1 liter of Methyl Ester
into a 2-liter plastic soft drink bottle. Gently pour about 500 milliliters of lukewarm water into
the bottle. Seal with a cap that will not leak. Gently rotate bottle end for end for about 30
seconds. After 30 seconds place the bottle upright. If you have been Gentle, the water and
Methyl Ester will separate immediately. You will notice the water is not clear. Wearing rubber
gloves, remove the cap, and using your thumb as a valve, turn the bottle upside down and drain
the water. Drain the water into a bucket and allow it to evaporate.
Fig 4.6 Washing Technique Adopted (Agitation Washing)
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23. Discard any residue. Repeat the process of adding 500 milliliters of lukewarm water,
gently shaking, and draining off the water four or five times. Each time that you repeat the
process, you should shake the mixture a little more vigorously and for a little longer, until by
the fifth washing you are shaking the mixture very strongly for about a minute or a little more.
Washed Methyl Ester is very cloudy, much lighter in color than the original Methyl Ester, and
looks terrible. After a day or two of settling and drying it will clear.
4.3.5 Drying of washed Methyl Ester
After the Methyl Ester is washed, it should be dried until it is clear. This can be done by
letting the Methyl Ester sit (covered) in a sunny location for a few days, or it may be heated to
about 120°F for a few hours. Reacted, washed, and dried Methyl Ester may be used in any diesel
engine. It should have a pH of close to 7, or chemically neutral and it should have no methanol
left in it.
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24. 5. DETERMINATION OF VISCOSITY
The Kinematic Viscosity of the oil samples was determined with a Redwood Viscometer
at temperatures ranging from 40°C to 100°C.
Fig 5.1 Determination of viscosity using Red Wood viscometer.
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25. Kinematic Viscosity was estimated by means of the following equation:
Kinematic Viscosity = [At – (B/t)] (5.1)
Where
A & B are Constants
t – Redwood seconds
Table 5.1 Kinematic Viscosity of some oil samples
Kinematic Viscosity (Centistokes)
Crude Soya bean oil Soya bean Methyl Ester
40°C 100°C 40°C 100°C
31.19 7.4 8.57 2.91
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26. 6. DETERMINATION OF VISCOSITY INDEX
Viscosity Index is a measure of a fluid's change of viscosity with temperature. The higher
the viscosity index, the smaller the relative change in viscosity with temperature. The Viscosity
Index was calculated for the samples crude and esters of Soya bean oil from Kinematic Viscosity
at 40°C and 100°C as per ASTM Standards D 2270 – 93
From ASTM Standards, the formula used to calculate the Viscosity Index of the oil is
given in the Equation
VI = [((antilog N) - 1) / 0.00715] +100
Where N = (log H – log U) / log Y
Y = kinematic viscosity at 100°C of the oil whose kinematic
Viscosity is to be calculated, mm2/s (cSt)
H = kinematic viscosity at 40°C of an oil of 100 viscosity
index having the same kinematic viscosity at 100°C as
the oil whose viscosity index is to be calculated mm2/s
Table 6.1 Calculation of Viscosity Index
Crude soya
bean oil SBME
Table Values from Standards H 52.88 11.50
Kinematic viscosity at 40°C U 31.19 8.57
Kinematic viscosity at 100°C Y 7.4 2.91
LogH – LogU 0.229276 0.127717
Log Y 0.869232 0.463893
N 0.263768 0.275316
Viscosity Index VI 216.86 223.77
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27. 7. RESULTS OF THE LUBRICANT PROPERTIES
Table 7.1 Results of the lubricant properties
Parameters Soya bean oil Soya bean
methyl ester
Kinematic viscosity at 40 deg. C 31.19cSt 8.57cSt
Kinematic viscosity at 100 deg. C 7.4cSt 2.91cSt
Viscosity index 216.86 223.77
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28. 8. CONCLUSION
The vegetable oils are having many advantages like high viscosity index, low friction
coefficient, high flash point, low volatile etc., over mineral oils, used as base stock for lubricants.
However, due to their low thermal and oxidative stabilities, their usage in engine applications is
limited. The chemical modification of the oil forms via. esterification reduces viscosity,
increases the viscosity index, and improves the thermal/ oxidation stability by reducing the poly
unsaturated fatty acids.
In this project work Soya bean oil is considered as a potential candidate for bio-lubricant
base stock based on the availability. The transesterification of Soya bean oil with alcohol
(Methanol) in the presence of base catalyst (NaOH) yielded Soya bean Methyl Ester (SBME)
which has superior thermo-oxidative properties than crude soya bean oil.
Hence, it is concluded that the ester forms of vegetable oils can be blended with mineral
oil for crankcase lubrication. Also, esters produced with higher order alcohols along with
suitable bio-degradable additives will replace the mineral / synthetic lubricants for engine
applications.
The future research may be in the areas of esterification of vegetable oils with higher
order alcohols, bio-degradable additives, and condition monitoring analysis of mineral oil-ester
blends.
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29. 9. REFERENCES
1. Aggarwal, J.S. and Verman, L.C. (1940), ‘Vegetable oils as lubricants’, Indian Ind.
Research Bull, Vol.18, pp. 5-25.
2. American Society for Testing & Materials standards
3. Fernando, S. and M. Hanna (2001), ‘Comparison of viscosity characteristics of soybean
oils with a mineral oil two-stroke engine lubricant’, Transactions of the ASAE.
4. Schuchardt, U., Sercheli, R. and Vargas, R.M. (1998), ‘Transesterification of vegetable
oils: a review’, Journal of Brazil Chemical Society, Vol. 9, pp.199– 210.
5. Van Gerpen J. (2005), ‘Biodiesel processing and production’ Fuel Process Technology
Vol.86, pp.97–107.
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